Improving the Resolution of Steady-State, Infrared-Based Thermal Interface Resistance Measurements Using High-Precision Metrology to Determine In-Situ TIM Thickness

2016 ◽  
Author(s):  
Ronald J. Warzoha ◽  
Andrew N. Smith ◽  
Maurice Harris
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Interfacial Thermal Resistance ◽  
Thermal Probe ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Measurement Systems ◽  
Thermal Interface Resistance ◽  
Order Of Magnitude

The performance characteristics of thermal interface materials (TIMs) are quickly outpacing our ability to measure them using steady-state techniques. In fact, scientists have turned to photothermal techniques like Time-domain Thermoreflectance (TDTR) to measure the impedance to heat flow across TIMs, namely due to their relatively low measurement uncertainties. However, such techniques are costly, require significant sample preparation, only measure local thermal impedances and are not yet equipped to measure thermal resistance as a function of pressure. Instead, it is desirable to maximize the resolution of traditional steady-state equipment for these types of measurements. In this work, we develop a more robust and accurate methodology to determine the temperature difference across the junction of a traditional steady-state apparatus using high accuracy measurements of in-situ TIM thickness in tandem with infrared thermography. This methodology eliminates a significant fraction of the uncertainty associated with the measurement of thermal interface resistance. Importantly, the use of this method improves the accuracy of the measurement device by an order of magnitude at interfacial thermal resistance values on the order of 1·10−6m2·K/W when compared to state-of-the-art, thermal probe-based measurement systems.

Maximum Resolution of a Probe-Based, Steady-State Thermal Interface Material Characterization Instrument

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Ronald J. Warzoha ◽  
Andrew N. Smith ◽  
Maurice Harris
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
High Performance ◽  
Heat Dissipation ◽  
Thermal Contact ◽  
Thermal Interface Material ◽  
Interfacial Thermal Resistance ◽  
Uniform Heat Flux ◽  
Thermal Probe ◽  
Thermal Interface

Thermal interface materials (TIMs) constitute a critical component for heat dissipation in electronic packaging systems. However, the extent to which a conventional steady-state thermal characterization apparatus can resolve the interfacial thermal resistance across current high-performance interfaces (RT < 1 mm2⋅K/W) is not clear. In this work, we quantify the minimum value of RT that can be measured with this instrument. We find that in order to increase the resolution of the measurement, the thermal resistance through the instrument's reference bars must be minimized relative to RT. This is practically achieved by reducing reference bar length. However, we purport that the minimization of reference bar length is limited by the effects of thermal probe intrusion along the primary measurement pathway. Using numerical simulations, we find that the characteristics of the probes and surrounding filler material can significantly impact the measurement of temperature along each reference bar. Moreover, we find that probes must be spaced 15 diameters apart to maintain a uniform heat flux at the interface, which limits the number of thermal probes that can be used for a given reference bar length. Within practical constraints, the minimum thermal resistance that can be measured with an ideal instrument is found to be 3 mm2⋅K/W. To verify these results, the thermal resistance across an indium heat spring material with an expected thermal contact resistance of ∼1 mm2⋅K/W is experimentally measured and found to differ by more than 100% when compared to manufacturer-reported values.

Characterization of a Liquid-Metal Micro Droplets Thermal Interface Material

2010 ◽  
Author(s):  
Amer M. Hamdan ◽  
Aric R. McLanahan ◽  
Robert F. Richards ◽  
Cecilia D. Richards
Keyword(s):  
Liquid Metal ◽  
Thermal Resistance ◽  
Contact Resistance ◽  
Applied Load ◽  
Thermal Interface Material ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Thermal Interface Resistance ◽  
Droplet Array

This work presents the characterization of a thermal interface material consisting of an array of mercury micro droplets deposited on a silicon die. Three arrays were tested, a 40 × 40 array (1600 grid) and two 20 × 20 arrays (400 grid). All arrays were assembled on a 4 × 4 mm2 silicon die. An experimental facility which measures the thermal resistance across the mercury array under steady state conditions is described. The thermal interface resistance of the arrays was characterized as a function of the applied load. A thermal interface resistance as low as 0.253 mm2 K W−1 was measured. A model to predict the thermal resistance of a liquid-metal micro droplet array was developed and compared to the experimental results. The model predicts the deformation of the droplet array under an applied load and then the geometry of the deformed droplets is used to predict the thermal resistance of the array. The contact resistance of the mercury arrays was estimated based on the experimental and model data. An average contact resistance was estimated to be 0.14 mm2 K W−1.

Characterization of Metallically Bonded Carbon Nanotube-Based Thermal Interface Materials Using a High Accuracy 1D Steady-State Technique

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Joseph R. Wasniewski ◽  
David H. Altman ◽  
Stephen L. Hodson ◽  
Timothy S. Fisher ◽  
Anuradha Bulusu ◽  
...  
Keyword(s):  
Steady State ◽  
High Performance ◽  
Applied Pressure ◽  
Test Facility ◽  
Thermal Interface Materials ◽  
Thermal Interface ◽  
Thermal Interface Resistance ◽  
Vertically Aligned ◽  
Performance Results ◽  
Interface Materials

The next generation of thermal interface materials (TIMs) are currently being developed to meet the increasing demands of high-powered semiconductor devices. In particular, a variety of nanostructured materials, such as carbon nanotubes (CNTs), are interesting due to their ability to provide low resistance heat transport from device-to-spreader and compliance between materials with dissimilar coefficients of thermal expansion (CTEs), but few application-ready configurations have been produced and tested. Recently, we have undertaken major efforts to develop functional nanothermal interface materials (nTIMs) based on short, vertically aligned CNTs grown on both sides of a thin interposer foil and interfaced with substrate materials via metallic bonding. A high-precision 1D steady-state test facility has been utilized to measure the performance of nTIM samples, and more importantly, to correlate performance to the controllable parameters. In this paper, we describe our material structures and the myriad permutations of parameters that have been investigated in their design. We report these nTIM thermal performance results, which include a best to-date thermal interface resistance measurement of 3.5 mm2 K/W, independent of applied pressure. This value is significantly better than a variety of commercially available, high-performance thermal pads and greases we tested, and compares favorably with the best results reported for CNT-based materials in an application-representative setting.

Flame propagation in nano-aluminum–water (nAl–H2O) mixtures: The role of thermal interface resistance

2019 ◽  
Vol 201 ◽  
pp. 160-169
Author(s):  
Murali Gopal Muraleedharan ◽  
Umesh Unnikrishnan ◽  
Asegun Henry ◽  
Vigor Yang
Keyword(s):  
Flame Propagation ◽  
Thermal Interface ◽  
Interface Resistance ◽  
Thermal Interface Resistance

Measurement of High-Performance Thermal Interfaces Using a Reduced Scale Steady-State Tester and Infrared Microscopy

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Andrew N. Smith ◽  
Nicholas R. Jankowski ◽  
Lauren M. Boteler
Keyword(s):  
Steady State ◽  
High Performance ◽  
Thermal Interface Materials ◽  
Interfacial Resistance ◽  
Heat Meter ◽  
Thermal Interface ◽  
Order Of Magnitude ◽  
Interface Materials ◽  
Reduced Scale ◽  
Magnitude Improvement

Thermal interface materials (TIMs) have reached values approaching the measurement uncertainty of standard ASTM D5470 based testers of approximately ±1 × 10−6 m2 K/W. This paper presents a miniature ASTM-type steady-state tester that was developed to address the resolution limits of standard testers by reducing the heat meter bar thickness and using infrared (IR) thermography to measure the temperature gradient along the heat meter bar. Thermal interfacial resistance measurements on the order of 1 × 10−6 m2 K/W with an order of magnitude improvement in the uncertainty of ±1 × 10−7 m2 K/W are demonstrated. These measurements were made on several TIMs with a thermal resistance as low as 1.14 × 10−6 m2 K/W.

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